1. Field of the Invention
The present invention relates to an image processor, an image processing method, and a program for executing the method, and more particularly to color processing and drawing techniques in a reflective color image production method for producing a color image as a hardcopy print.
2. Description of the Related Art
Recently, a so-called color print system, which employs a printer utilizing digital exposure, that is, a digital photographic printer so that a photographic image is digitally output as a color hardcopy, has been commercially distributed and utilized. In this color print system, an image recorded on a photographic film such as a negative film or a reversal film is photoelectrically read out. The readout image is converted to a digital signal, which is then subjected to various image processing (digital signal processing) so as to obtain image data for recording. A photosensitive material is subjected to scanning exposure with recording light which is modulated in accordance with the obtained image data so as to record an image (latent image), thereby obtaining a (finished) print.
In such a system, the brightest part of image data is set so as to correspond to the minimum density of an output medium in order to widely set a reproduction range of the image Herein, the brightest part indicates a point where each of R, G and B has a value of 255 (255, 255, 255) in the case where one pixel of digital image data is represented by 8-bit data, for example. The minimum density of the output medium corresponds to a density of white in an unexposed part in the case where the output medium is a color paper, whereas it corresponds to a density of a base in its undrawn portion in the case where the output medium is an IJ (ink jet) paper.
As described above, the correspondence of the brightest part of the image data to the minimum density of the output medium is preferred in view of simplification of a printer output algorithm because such correspondence allows the individual control of three colors (R, G, B) on the one-dimensional table. In calorimetric description, the brightest point can be represented as a point where Y or L* (CIELAB) achievable on the output medium exhibits its maximum value.
However, some output mediums have a problem in that a tint is perceived in a blank part (brightest part) of the image due to correspondence of the brightest part of the image to the brightest point of the output medium as described above, resulting in insufficient final image quality.